Aaron Cruden completes New Zealand's perfect season with the winning kick against Ireland in added time. Photograph: Phil Walter/Getty Images

On Saturday at Wembley it was the league players of New Zealand who took it to the last play and here in Dublin it was union's turn. The clock had turned red and still the All Blacks kept running, forcing themselves to their feet from the pile-up where they had earned themselves a penalty and running into open play, passing, probing and finding the gap that counted.

For the league Kiwis there is a final to come, while for Richie McCaw's players there is a place in the record books and a rest, a summer off back home. They have won 14 out of 14, a complete set of wins, in the year, never before achieved in the professional age. It is a record to savour, a balm for nerves shredded here.

The All Blacks have been rattled in each of their three games in Europe, by France, England and now Ireland – but never like here. Before they could ease into their free-flowing rhythm, they were three tries down. It stopped being a jolt long before Rob Kearney ran on to a knock-on by Israel Dagg and was fast turning into the ultimate test of powers of recovery.

That they passed the test puts a sheen on the year and at the same time offers comfort to the teams that remain in pursuit of the standards set. The ABs are unbeaten but not quite as unbeatable as they appeared when they beat South Africa in the finale of the Rugby Championship. In Johannesburg they swept imperiously to a title; in Dublin they could barely raise an arm in triumph. Blood leaked from the brow of McCaw, and from the eye of the try-scorer, Ben Franks. A lot of the red stuff had to be spilt here.

It is unlikely disciplinary action will be taken against any players who go out into Dublin for a late-night drink but it is equally unlikely any of the players involved here will have the energy left to toast themselves yet. The bodily bruises will be matched by the mental exhaustion of keeping their discipline and their thinking processes intact as the stared defeat in the face.

They made mistakes, blasted off their feet by the aggression of Sean O'Brien and Cian Healy, the prop who could not bring himself in the week to utter the words "All Blacks". He had a point. Holding them in something less than awe seemed to work for an Ireland team who were unrecognisable from the sorry side who had slumped to defeat against Australia.

Ma'a Nonu, who has bounced a few tacklers around over the years, found himself treated with disrespect by the bearded Gordon D'Arcy, who had declared himself unready for the contemplation of retirement. Not many truly believed he was that far away from the end of his career; even fewer believed he had a performance like this left in him. They believe it now, because the centre was everywhere, asking questions and physically imposing himself.

In the end, in the 81st minute of their exhaustion, discipline deserted the Irish. For the second time they charged a conversion, deeming a twitch by Aaron Cruden to be the start of his run-up. Having pushed the kick – the conversion necessary for the 100 per cent season – to the right, the fly-half was given a second chance by the referee, Nigel Owens. It was the most un-frenzied conclusion to a game that had bounced with drama from start to finish. Cruden, of course, nailed his second attempt.

And with that, history was made. The smallest player on the field turned and walked off. Cool as you like. There were a few smiles but this was not greeted as if a national lottery was landed. What pressure, what stress? There seems to be a unique quality to the southern sporting psyche: not to be carried away by euphoria, not to give way to tension but to embrace the opportunity. In a penalty shoot-out there would be 15 Kiwi hands raised to take a shot.

There was an adjustment to their game, if not their thinking processes, along the way. Under pressure in Paris and at Twickenham the All Blacks made more tackles than their opponents and had less possession. In the second half they did not have to make that many tackles, so complete was their hold on the ball. It is not easy to work out just how deliberate this was but never before had the All Blacks had to come from so far behind.

They kicked a lot less than usual, while Ireland kicked more in the second half than they had in the first. It was a role-reversal, an inversion of the trends as New Zealand grappled with this seriously unexpected challenge. They emerged the victors, their skills overcoming their fatigue as they strung together the passes that put Ryan Crotty over for the final try. Tiredness would not be the victor; blood would be spilt and skill would win the day. Magnificent, truly magnificent.